Question

$(1,2)$ is a point on the line.

• A. $x+2y=5$
• B. $2x+y=5$
• C. $4x–y=5$

Answer 1

The correct option is A $x+2y=5$

Each solution of a linear equation in two variables corresponds to a point on the line representing the equation, and vice-versa.
Substitute $(1,2)$ in the options given to check if it satisfies the given equations.
Substituting $(1,2)$ in $x+2y=5,$ we have
$1+2\left(2\right)=5.$
$\therefore (1,2)$ lies on the line $x+2y=5.$
Substituting $(1,2)$ in $2x+y=5,$ we have
$2\left(1\right)+2=4\ne 5.$
$\therefore (1,2)$ does not lie on the line $2x+y=5.$
Similarly, $(1,2)$ does not lie on the line $4x–y=5$ as $4\left(1\right)–2=2\ne 5.$